1. Field of the Invention
The present invention relates to an electrical connector having a floating structure.
2. Description of the Related Art
As the performance and multifunctionality of automobile electronic appliances and consumer electronic appliances have increased, electrical connectors for connecting printed circuit boards (hereinafter, referred to as “boards”) to each other are increasingly used. Moreover, as electronic appliances have been reduced in size, boards have also been reduced in size and component packing density has increased. At the same time, it is necessary to connect the boards with high reliability.
A floating structure is a known technology for increasing the connection reliability of electrical connectors. In general, a floating structure includes a “fixed housing” mounted on a board, a “movable housing” to be fitted with a connection object, and “terminals”. Each of the terminals includes a movable portion that is elastic and that holds the fixed housing and the movable housing in such a way that the fixed housing and the movable housing are displaceable relative to each other. With the floating structure, the movable portion, which is displaceable, can reduce the effect of an error in the positions of the boards are attached relative to each other. Moreover, the movable portion can absorb displacement of the boards relative to each other due to vibration or impact. Therefore, occurrence of poor contact between terminals and cracking and detachment of solder, which is used to join terminals to the board, can be reduced (see Japanese Unexamined Patent Application Publication No. 2007-109600).
Also regarding the electrical connectors having the floating structure and having high connection reliability, reduction in size is needed as electronic appliances have been reduced in size. However, the movable portion, which is a key component of the floating structure, is one of factors that limit reduction in size.
The reason for this is as follows. An electrical connector has a rectangular shape, and a large number of terminals are arranged side by side along the longitudinal direction of the housing in such a way that the plate surfaces of the terminals extend parallel to each other. Typically, the movable portions of the terminals are disposed between a fixed housing and a movable housing in the transverse direction of the housing. Accordingly, it is necessary to provide a movable space, in which the movable portions are disposed and are allowed to be elastically deformed, between the fixed housing and the movable housing. Moreover, the size of the movable space cannot be reduced beyond a certain limit so that the fixed housing and the movable housing can be displaced relative to each other by a sufficient amount in the movable space. Therefore, it is difficult to reduce the size of the entirety of the electrical connector by reducing the size of movable space while maintaining the existing connector structure.
Moreover, while the electrical connector is being soldered to a board, flux may flow through small gaps between terminal attachment grooves of the housing and terminals attached to the grooves due to capillary action, and the flux may reach the contact-point portion and cause defective contact between the terminals. This may be suppressed by forming large gaps, in which capillary action cannot occur, between the terminals and the housing. In this case, however, the size of the electrical connector is increased by the amount of increase in the size of the gaps.